| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Jiang, Cong, et al.
(författare)
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F-doped LiNi0.8Co0.15Al0.05O2-? : cathodes with enhanced ORR catalytic activity for LT-SOFCs
- 2023
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 940
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Tidskriftsartikel (refereegranskat)abstract
- Developing highly effective catalysts for oxygen reduction reaction (ORR) is crucial to enable the low-temperature operation of solid oxide fuel cells (SOFCs). Recent studies have proposed a promising O2-/H+/e- conducting oxide, LiNi0.8Co0.15Al0.05O2-delta (LNCA) with good ORR catalytic activity for SOFC cathode uses. Herein, to further optimize the cathode functionality of LNCA, a fluorine anion (F-) doping strategy is ap-plied to develop highly active LNCAF0.1 and LNCAF0.2 cathodes for Sm-doped ceria (SDC) electrolyte-based SOFCs. It is found the successful doping of F- in the oxygen site of LNCA leads to improved oxygen ionic conductivity and facilitated surface exchange and bulk diffusion of oxygen in LNCAF0.1 and LNCAF0.2, which thus gain distinctly promoted ORR catalytic activity at 450-550 degrees C, as confirmed by the decreased area specific resistances (ASR) and activation energy on symmetrical cells. The as-fabricated two SDC-based SOFCs with LNCAF0.1 and LNCAF0.2 cathodes exhibit peak power densities of 497 and 591 mW cm-2 at 550 degrees C, respectively, which are higher than that of the cell with LNCA cathode. Furthermore, the single cell with the best-performing LNCAF0.2 cathode demonstrates a good stability for 110 h at 550 degrees C. The present study thus provides a feasible strategy of F anion doping to promote the ORR catalytic activity of LNCA cathode for developing low-temperature SOFCs.
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| 3. |
- Wang, Hao, et al.
(författare)
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In-situ growth of low-dimensional perovskite-based insular nanocrystals for highly efficient light emitting diodes
- 2023
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Ingår i: Light. - : SPRINGERNATURE. - 2095-5545 .- 2047-7538. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Regulation of perovskite growth plays a critical role in the development of high-performance optoelectronic devices. However, judicious control of the grain growth for perovskite light emitting diodes is elusive due to its multiple requirements in terms of morphology, composition, and defect. Herein, we demonstrate a supramolecular dynamic coordination strategy to regulate perovskite crystallization. The combined use of crown ether and sodium trifluoroacetate can coordinate with A site and B site cations in ABX(3) perovskite, respectively. The formation of supramolecular structure retard perovskite nucleation, while the transformation of supramolecular intermediate structure enables the release of components for slow perovskite growth. This judicious control enables a segmented growth, inducing the growth of insular nanocrystal consist of low-dimensional structure. Light emitting diode based on this perovskite film eventually brings a peak external quantum efficiency up to 23.9%, ranking among the highest efficiency achieved. The homogeneous nano-island structure also enables high-efficiency large area (1 cm(2)) device up to 21.6%, and a record high value of 13.6% for highly semi-transparent ones.
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| 4. |
- Xiong, Shaobing, et al.
(författare)
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Direct Observation on p- to n-Type Transformation of Perovskite Surface Region during Defect Passivation Driving High Photovoltaic Efficiency
- 2021
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Ingår i: Joule. - : CELL PRESS. - 2542-4351. ; 5:2, s. 467-480
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Tidskriftsartikel (refereegranskat)abstract
- Perovskite solar cells (PSCs) suffer from significant nonradiative recombination, limiting their power conversion efficiencies. Here, for the first time, we directly observe a complete transformation of perovskite MAPbI(3) surface region energetics from p- to n-type during defect passivation caused by natural additive capsaicin, attributed to the spontaneous formation of a p-n homojunction in perovskite active layer. We demonstrate that the p-n homojunction locates at similar to 100 nm below perovskite surface. The energetics transformation and defect passivation promote charge transport in bulk perovskite layer and at perovskite/PCBM interface, suppressing both defect-assisted recombination and interface carrier recombination. As a result, an efficiency of 21.88% and a fill factor of 83.81% with excellent device stability are achieved, both values are the highest records for polycrystalline MAPbI(3) based p-i-n PSCs reported to date. The proposed new concept of synergetic defect passivation and energetic modification via additive provides a huge potential for further improvement of PSC performance.
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